Composite materials are well known in dentistry and can be used for example as filling materials, permanent cements or temporary crown and bridge materials. Depending on indication the different composite materials can be differentiated by their respective filler contents.
Filling composites are typically highly filled materials which are characterized by good mechanical properties like low abrasion (low wear). Unfortunately due to the high filler loading these materials sometimes tend to be brittle.
Temporary crown and bridge materials have a lower filler content compared to filling composites. This often results in an improved elasticity and a higher fracture resistance, but often goes along with an increased abrasion or wear which prevents a long-term use of these materials.
Commercially available lab composite materials for the manufacturing of dental restorations such as crowns cannot be used in an in-office or chair-side procedure and require the involvement of an external dental laboratory. Alternatively composite milling blocks such as Paradigm™ MZ 100 (3M ESPE) can be used in an in-office or chairside procedure but require an investment in considerable expensive CAD/CAM technology.
Thus, there is a need for a material that combines the properties of the materials described above which can be used for an in-office or chair-side fabrication of composite crowns and bridges without the need for an investment in CAD/CAM technology.
Further, patients and dentists nowadays have an increasing demand for long-lasting dental restorations.
EP 2 167 013 A1 (3M) relates to dental compositions containing a polyfunctional (meth)acrylate comprising urethane, urea or amide groups, methods of production and use thereof.
US 2005/0234148 A1 (Heraeus) describes agglomerated inorganic fillers for dental materials consisting of 0.5 to 50 μm agglomerates of 200 to 7000 nm inorganic particles, which are fused at their interfaces to at least one adjacent particle. WO 2012/057917 A1 (3M) describes a preformed semi-finished dental article comprising an uncured dental restoration composition comprising a certain resin system at least 50 wt.-% of nanocluster filler, wherein the uncured dental restoration composition has a first shape that is sufficiently malleable to be formed into a second shape.
U.S. Pat. No. 6,730,156 B1 (Windisch et al.) relates to a filler comprising a substantially amorphous cluster comprising non-heavy oxide particles and heavy metal oxide. The filler can be mixed into a hardenable resin to provide radiopaque dental materials having desirable strength and aesthetic character.